[PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[Jose Ignacio Tornos Martinez]

Some Qualcomm PCIe devices (WCN6855/WCN7850 WiFi cards, SDX62/SDX65 modems)
lack working reset methods for VFIO passthrough scenarios. These devices
have no FLR capability, advertise NoSoftRst+ (blocking PM reset), and have
broken bus reset.

The problem manifests in VFIO passthrough scenarios:

- WCN6855 (17cb:1103) and WCN7850 (17cb:1107) WiFi devices:
  Normal VM operation works fine, including clean shutdown/reboot.
  However, when the VM terminates uncleanly (crash, force-off), VFIO
  attempts to reset the device before it can be assigned to another VM.
  Without a working reset method, the device remains in an undefined state,
  preventing reuse.

- SDX62/SDX65 (17cb:0308) 5G modems: Never successfully initialize even
  on first VM assignment without proper reset capability.

Add device-specific reset methods using BAR-space hardware reset registers
that exist in these devices:

- WCN6855/WCN7850 WiFi devices use SoC global reset via BAR0 (sequence from
  ath11k/ath12k driver: ath11k_pci_soc_global_reset(), ath11k_pci_sw_reset(),
  ath11k_mhi_set_mhictrl_reset()):
  - Write/clear reset bit at offset 0x3008
  - Wait for PCIe link recovery (up to 5 seconds)
  - Clear MHI controller SYSERR status at offset 0x38

- SDX62/SDX65 modem devices use MHI SoC reset via BAR0 (sequence from MHI
  driver: mhi_soc_reset(), mhi_pci_reset_prepare()):
  - Write reset request to offset 0xb0
  - Wait 2 seconds for reset completion

These are true hardware reset mechanisms (not power management or firmware
error recovery), providing proper device reset for VFIO scenarios.

Testing was performed on desktop platforms with M.2 WiFi and modem cards
using M.2-to-PCIe adapters, including extensive force-reset cycling to
verify stability.

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
---
v11: Address Manivannan Sadhasivam feedback:
  - Remove unused QUALCOMM_WIFI_MHISTATUS define
  - Use PCI_ERROR_RESPONSE instead of 0xffffffff
  - Sort device IDs in ascending order (0x0308, 0x1103, 0x1107)
v10: https://lore.kernel.org/all/20260623183115.1585273-1-jtornosm@redhat.com/

 drivers/pci/quirks.c | 117 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 431c021d7414..0de606366200 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4240,6 +4240,120 @@ static int reset_hinic_vf_dev(struct pci_dev *pdev, bool probe)
 	return 0;
 }
 
+#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET	0x3008
+#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V	BIT(0)
+#define QUALCOMM_WIFI_MHICTRL			0x38
+#define QUALCOMM_WIFI_MHICTRL_RESET_MASK	0x2
+
+/*
+ * Qualcomm WiFi device-specific reset using SoC global reset via BAR0
+ * registers.
+ */
+static int reset_qualcomm_wifi(struct pci_dev *pdev, bool probe)
+{
+	bool link_recovered = false;
+	unsigned long timeout;
+	void __iomem *bar;
+	u32 val;
+	u16 cmd;
+
+	if (probe)
+		return 0;
+
+	if (pdev->current_state != PCI_D0)
+		return -EINVAL;
+
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
+
+	bar = pci_iomap(pdev, 0, 0);
+	if (!bar) {
+		pci_write_config_word(pdev, PCI_COMMAND, cmd);
+		return -ENODEV;
+	}
+
+	val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+	val |= QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
+	iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+	ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+
+	msleep(10);
+
+	val &= ~QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
+	iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+	ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+
+	msleep(10);
+
+	timeout = jiffies + msecs_to_jiffies(5000);
+	while (time_before(jiffies, timeout)) {
+		val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
+		if (val != PCI_ERROR_RESPONSE) {
+			link_recovered = true;
+			break;
+		}
+		msleep(20);
+	}
+
+	if (!link_recovered) {
+		pci_err(pdev, "PCIe link failed to recover after reset\n");
+		goto out_restore;
+	}
+
+	/* After SOC_GLOBAL_RESET, MHISTATUS may still have SYSERR bit set
+	 * and thus need to set MHICTRL_RESET to clear SYSERR.
+	 */
+	iowrite32(QUALCOMM_WIFI_MHICTRL_RESET_MASK, bar + QUALCOMM_WIFI_MHICTRL);
+	ioread32(bar + QUALCOMM_WIFI_MHICTRL);
+
+	msleep(10);
+
+out_restore:
+	pci_iounmap(pdev, bar);
+	pci_write_config_word(pdev, PCI_COMMAND, cmd);
+
+	return link_recovered ? 0 : -ETIMEDOUT;
+}
+
+#define MHI_SOC_RESET_REQ_OFFSET		0xb0
+#define MHI_SOC_RESET_REQ			BIT(0)
+
+/*
+ * Qualcomm modem device-specific reset using MHI SoC reset via BAR0
+ * register.
+ */
+static int reset_qualcomm_modem(struct pci_dev *pdev, bool probe)
+{
+	void __iomem *bar;
+	u16 cmd;
+
+	if (probe)
+		return 0;
+
+	if (pdev->current_state != PCI_D0)
+		return -EINVAL;
+
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
+
+	bar = pci_iomap(pdev, 0, 0);
+	if (!bar) {
+		pci_write_config_word(pdev, PCI_COMMAND, cmd);
+		return -ENODEV;
+	}
+
+	iowrite32(MHI_SOC_RESET_REQ, bar + MHI_SOC_RESET_REQ_OFFSET);
+	ioread32(bar + MHI_SOC_RESET_REQ_OFFSET);
+
+	/* Be sure device reset has been executed */
+	msleep(2000);
+
+	pci_iounmap(pdev, bar);
+	pci_write_config_word(pdev, PCI_COMMAND, cmd);
+
+	return 0;
+}
+
 static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
 	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
 		 reset_intel_82599_sfp_virtfn },
@@ -4255,6 +4369,9 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
 		reset_chelsio_generic_dev },
 	{ PCI_VENDOR_ID_HUAWEI, PCI_DEVICE_ID_HINIC_VF,
 		reset_hinic_vf_dev },
+	{ PCI_VENDOR_ID_QCOM, 0x0308, reset_qualcomm_modem }, /* SDX62/SDX65 modems */
+	{ PCI_VENDOR_ID_QCOM, 0x1103, reset_qualcomm_wifi },  /* WCN6855 WiFi */
+	{ PCI_VENDOR_ID_QCOM, 0x1107, reset_qualcomm_wifi },  /* WCN7850 WiFi */
 	{ 0 }
 };
 
-- 
2.54.0

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[Manivannan Sadhasivam]

On Fri, Jun 26, 2026 at 07:50:23AM +0200, Jose Ignacio Tornos Martinez wrote:
> Some Qualcomm PCIe devices (WCN6855/WCN7850 WiFi cards, SDX62/SDX65 modems)
> lack working reset methods for VFIO passthrough scenarios. These devices
> have no FLR capability, advertise NoSoftRst+ (blocking PM reset), and have
> broken bus reset.
> 
> The problem manifests in VFIO passthrough scenarios:
> 
> - WCN6855 (17cb:1103) and WCN7850 (17cb:1107) WiFi devices:
>   Normal VM operation works fine, including clean shutdown/reboot.
>   However, when the VM terminates uncleanly (crash, force-off), VFIO
>   attempts to reset the device before it can be assigned to another VM.
>   Without a working reset method, the device remains in an undefined state,
>   preventing reuse.
> 
> - SDX62/SDX65 (17cb:0308) 5G modems: Never successfully initialize even
>   on first VM assignment without proper reset capability.
> 
> Add device-specific reset methods using BAR-space hardware reset registers
> that exist in these devices:
> 
> - WCN6855/WCN7850 WiFi devices use SoC global reset via BAR0 (sequence from
>   ath11k/ath12k driver: ath11k_pci_soc_global_reset(), ath11k_pci_sw_reset(),
>   ath11k_mhi_set_mhictrl_reset()):
>   - Write/clear reset bit at offset 0x3008
>   - Wait for PCIe link recovery (up to 5 seconds)
>   - Clear MHI controller SYSERR status at offset 0x38
> 
> - SDX62/SDX65 modem devices use MHI SoC reset via BAR0 (sequence from MHI
>   driver: mhi_soc_reset(), mhi_pci_reset_prepare()):
>   - Write reset request to offset 0xb0
>   - Wait 2 seconds for reset completion
> 
> These are true hardware reset mechanisms (not power management or firmware
> error recovery), providing proper device reset for VFIO scenarios.
> 
> Testing was performed on desktop platforms with M.2 WiFi and modem cards
> using M.2-to-PCIe adapters, including extensive force-reset cycling to
> verify stability.
> 
> Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Couple of comments below, including one bug due to my previous suggestion. Once
those are addressed, feel free to add:

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

> ---
> v11: Address Manivannan Sadhasivam feedback:
>   - Remove unused QUALCOMM_WIFI_MHISTATUS define
>   - Use PCI_ERROR_RESPONSE instead of 0xffffffff
>   - Sort device IDs in ascending order (0x0308, 0x1103, 0x1107)
> v10: https://lore.kernel.org/all/20260623183115.1585273-1-jtornosm@redhat.com/
> 
>  drivers/pci/quirks.c | 117 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 117 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 431c021d7414..0de606366200 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4240,6 +4240,120 @@ static int reset_hinic_vf_dev(struct pci_dev *pdev, bool probe)
>  	return 0;
>  }
>  
> +#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET	0x3008
> +#define QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V	BIT(0)
> +#define QUALCOMM_WIFI_MHICTRL			0x38
> +#define QUALCOMM_WIFI_MHICTRL_RESET_MASK	0x2

Qcom calls these WiFi devices as WLAN devices. So I'd prefer to use this term
all around even for function names.

> +
> +/*
> + * Qualcomm WiFi device-specific reset using SoC global reset via BAR0
> + * registers.
> + */
> +static int reset_qualcomm_wifi(struct pci_dev *pdev, bool probe)
> +{
> +	bool link_recovered = false;
> +	unsigned long timeout;
> +	void __iomem *bar;
> +	u32 val;
> +	u16 cmd;
> +
> +	if (probe)
> +		return 0;
> +
> +	if (pdev->current_state != PCI_D0)
> +		return -EINVAL;
> +
> +	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
> +	pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
> +
> +	bar = pci_iomap(pdev, 0, 0);
> +	if (!bar) {
> +		pci_write_config_word(pdev, PCI_COMMAND, cmd);
> +		return -ENODEV;
> +	}
> +
> +	val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +	val |= QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
> +	iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +	ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +
> +	msleep(10);
> +
> +	val &= ~QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
> +	iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +	ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +
> +	msleep(10);
> +
> +	timeout = jiffies + msecs_to_jiffies(5000);
> +	while (time_before(jiffies, timeout)) {
> +		val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> +		if (val != PCI_ERROR_RESPONSE) {

As Sashiko also pointed out, this will always evaluate to true due to
PCI_ERROR_RESPONSE being ~0ULL. Please use:

	if (!PCI_POSSIBLE_ERROR(val))

Sorry for the wrong suggestion earlier.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[Jose Ignacio Tornos Martinez]

Hi Mani,

No worries! v12 with the fix and WLAN renaming is on the way.
Thanks for catching it and your help

Best regards
Jose Ignacio

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[kernel test robot]

Hi Jose,

kernel test robot noticed the following build warnings:

[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v7.2-rc6 next-20260807]
[cannot apply to linux-review/Jose-Ignacio-Tornos-Martinez/Add-device-specific-reset-for-Qualcomm-devices/20260804-001013]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jose-Ignacio-Tornos-Martinez/PCI-Add-device-specific-reset-for-Qualcomm-devices/20260810-131417
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20260626055023.197470-1-jtornosm%40redhat.com
patch subject: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices
config: loongarch-defconfig (https://download.01.org/0day-ci/archive/20260810/202608101710.4bALXXJf-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 12df34b8469b8095359de8c249cb1b2753fadeea)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260810/202608101710.4bALXXJf-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202608101710.4bALXXJf-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/pci/quirks.c:4278:11: warning: result of comparison of constant 18446744073709551615 with expression of type 'u32' (aka 'unsigned int') is always true [-Wtautological-constant-out-of-range-compare]
    4278 |                 if (val != PCI_ERROR_RESPONSE) {
         |                     ~~~ ^  ~~~~~~~~~~~~~~~~~~
   1 warning generated.


vim +4278 drivers/pci/quirks.c

  4234	
  4235	/*
  4236	 * Qualcomm WiFi device-specific reset using SoC global reset via BAR0
  4237	 * registers.
  4238	 */
  4239	static int reset_qualcomm_wifi(struct pci_dev *pdev, bool probe)
  4240	{
  4241		bool link_recovered = false;
  4242		unsigned long timeout;
  4243		void __iomem *bar;
  4244		u32 val;
  4245		u16 cmd;
  4246	
  4247		if (probe)
  4248			return 0;
  4249	
  4250		if (pdev->current_state != PCI_D0)
  4251			return -EINVAL;
  4252	
  4253		pci_read_config_word(pdev, PCI_COMMAND, &cmd);
  4254		pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
  4255	
  4256		bar = pci_iomap(pdev, 0, 0);
  4257		if (!bar) {
  4258			pci_write_config_word(pdev, PCI_COMMAND, cmd);
  4259			return -ENODEV;
  4260		}
  4261	
  4262		val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4263		val |= QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
  4264		iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4265		ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4266	
  4267		msleep(10);
  4268	
  4269		val &= ~QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
  4270		iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4271		ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4272	
  4273		msleep(10);
  4274	
  4275		timeout = jiffies + msecs_to_jiffies(5000);
  4276		while (time_before(jiffies, timeout)) {
  4277			val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> 4278			if (val != PCI_ERROR_RESPONSE) {
  4279				link_recovered = true;
  4280				break;
  4281			}
  4282			msleep(20);
  4283		}
  4284	
  4285		if (!link_recovered) {
  4286			pci_err(pdev, "PCIe link failed to recover after reset\n");
  4287			goto out_restore;
  4288		}
  4289	
  4290		/* After SOC_GLOBAL_RESET, MHISTATUS may still have SYSERR bit set
  4291		 * and thus need to set MHICTRL_RESET to clear SYSERR.
  4292		 */
  4293		iowrite32(QUALCOMM_WIFI_MHICTRL_RESET_MASK, bar + QUALCOMM_WIFI_MHICTRL);
  4294		ioread32(bar + QUALCOMM_WIFI_MHICTRL);
  4295	
  4296		msleep(10);
  4297	
  4298	out_restore:
  4299		pci_iounmap(pdev, bar);
  4300		pci_write_config_word(pdev, PCI_COMMAND, cmd);
  4301	
  4302		return link_recovered ? 0 : -ETIMEDOUT;
  4303	}
  4304	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[Jose Ignacio Tornos Martinez]

Please, use the latest version (v13):
https://lore.kernel.org/all/20260721081301.205374-1-jtornosm@redhat.com/
That and more things are fixed there.

Thanks

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[kernel test robot]

Hi Jose,

kernel test robot noticed the following build warnings:

[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v7.2-rc6 next-20260807]
[cannot apply to linux-review/Jose-Ignacio-Tornos-Martinez/Add-device-specific-reset-for-Qualcomm-devices/20260804-001013]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jose-Ignacio-Tornos-Martinez/PCI-Add-device-specific-reset-for-Qualcomm-devices/20260810-131417
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20260626055023.197470-1-jtornosm%40redhat.com
patch subject: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices
config: um-randconfig-r073-20260810 (https://download.01.org/0day-ci/archive/20260811/202608110204.wb17Qqit-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
smatch: v0.5.0-9187-g5189e3fb

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202608110204.wb17Qqit-lkp@intel.com/

smatch warnings:
drivers/pci/quirks.c:4278 reset_qualcomm_wifi() warn: always true condition '(val != (~0)) => (0-u32max != u64max)'

vim +4278 drivers/pci/quirks.c

  4234	
  4235	/*
  4236	 * Qualcomm WiFi device-specific reset using SoC global reset via BAR0
  4237	 * registers.
  4238	 */
  4239	static int reset_qualcomm_wifi(struct pci_dev *pdev, bool probe)
  4240	{
  4241		bool link_recovered = false;
  4242		unsigned long timeout;
  4243		void __iomem *bar;
  4244		u32 val;
  4245		u16 cmd;
  4246	
  4247		if (probe)
  4248			return 0;
  4249	
  4250		if (pdev->current_state != PCI_D0)
  4251			return -EINVAL;
  4252	
  4253		pci_read_config_word(pdev, PCI_COMMAND, &cmd);
  4254		pci_write_config_word(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
  4255	
  4256		bar = pci_iomap(pdev, 0, 0);
  4257		if (!bar) {
  4258			pci_write_config_word(pdev, PCI_COMMAND, cmd);
  4259			return -ENODEV;
  4260		}
  4261	
  4262		val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4263		val |= QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
  4264		iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4265		ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4266	
  4267		msleep(10);
  4268	
  4269		val &= ~QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET_V;
  4270		iowrite32(val, bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4271		ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
  4272	
  4273		msleep(10);
  4274	
  4275		timeout = jiffies + msecs_to_jiffies(5000);
  4276		while (time_before(jiffies, timeout)) {
  4277			val = ioread32(bar + QUALCOMM_WIFI_PCIE_SOC_GLOBAL_RESET);
> 4278			if (val != PCI_ERROR_RESPONSE) {
  4279				link_recovered = true;
  4280				break;
  4281			}
  4282			msleep(20);
  4283		}
  4284	
  4285		if (!link_recovered) {
  4286			pci_err(pdev, "PCIe link failed to recover after reset\n");
  4287			goto out_restore;
  4288		}
  4289	
  4290		/* After SOC_GLOBAL_RESET, MHISTATUS may still have SYSERR bit set
  4291		 * and thus need to set MHICTRL_RESET to clear SYSERR.
  4292		 */
  4293		iowrite32(QUALCOMM_WIFI_MHICTRL_RESET_MASK, bar + QUALCOMM_WIFI_MHICTRL);
  4294		ioread32(bar + QUALCOMM_WIFI_MHICTRL);
  4295	
  4296		msleep(10);
  4297	
  4298	out_restore:
  4299		pci_iounmap(pdev, bar);
  4300		pci_write_config_word(pdev, PCI_COMMAND, cmd);
  4301	
  4302		return link_recovered ? 0 : -ETIMEDOUT;
  4303	}
  4304	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v11] PCI: Add device-specific reset for Qualcomm devices

[Jose Ignacio Tornos Martinez]

Please, use the latest version (v13):
https://lore.kernel.org/all/20260721081301.205374-1-jtornosm@redhat.com/
That and more things are fixed there.

Thanks